Volume control apparatus for a singletone electronic musical instrument



'Aplll 15, 1969 GOQDALE 3,439,106

VOLUME CONTROL APPARATUS FOR A SINGLE-TONE ELECT IC MUSICAL INSTRUMENT v ed Jan. 4, 1965 /IO M AUDIO TONE GENERATOR VOLUME I MP CONTROL MEANS SPEAKER FIG.2

f VOLUME CONTROL MEANS J l 1E- 1 20 1 I ,-26 I I MIR FLOW 25 Dc I I r 4 AMPLIFIER l I I F m I I PHOTOSENSITIVE CELL f & j I AUDIO I/lll/ 'AMPLIFIER AND I SPEAKER INVENTOR I EDMUND E. GOODALE,

BY I

HIS ATTORNEY.

United States Patent US. Cl. 84-1.27 6 Claims ABSTRACT OF THE DISCLOSURE In a monophonic electronic musical instrument, breath control is utilized for controlling the volume of an audio frequency amplifier.

My invention relates to a monophonic electronic musical instrument, and more particularly to apparatus for controlling the volume of sound produced by the instrument.

Polyphonic electronic musical devices, such as the electronic organ, have enjoyed great commercial success. However, monophonic electronic musical instruments of the type with which my invention is concerned have not appeared as a successful product on the consumer market. It is believed that a primary reason for this lack of success lies in the inadequacy of prior devices as to the means employed for controlling the volume of the sound produced. Volume control of an electronic musical instrument of the monophonic type must necessarily be very complex if the volume variations of the imitated instrument are to be reproduced with a high degree of verisimilitude. For example, with an instrument such as a clarinet, tones are started and stopped with great rapidity by the tongue of the player. In addition, the volume is subject to irregular variations at high speeds. Prior to my invention no electronic musical instrument of the monophonic variety has included completely satisfactory volume control apparatus.

Prior devices have generally utilized hand or footoperated volume controls. However, if foot controls are employed, the pedal dexterity which is required to simulate the rapid and subtle variations in volume of a conventional instrument are beyond the attainment of the average player. Hand controls are unsatisfactory simply because both hands are needed to operate the pitch controls for the instrument. It is noted that at least one prior art patent teaches the use of a volume control arrangement located in the mouthpiece of the instrument. This arrangement comprises a rheostat controlled by lip pressure upon the mouthpiece. Whereas this arrangement would probably be satisfactory for gradual volume transitions, it would appear that rapid changes in volume could be accomplished with this arrangement only with great difliculty. Also, learning to control volume by lip pressure, rather than by the normal method of breathing, would demand additional skill and powers of adaptation.

Accordingly, it is an object of my invention to provide a monophonic electronic musical instrument having volume control apparatus which is actuated solely by the breath of the player.

It is another object of my invention to provide a monophonic electronic musical instrument having volume control apparatus which can be operated by the player of a conventional instrument very naturally and with little difiiculty of adaptation.

It is a further object of my invention to provide a monophonic electronic musical instrument having volume control apparatus which functions both to turn the instrument on or off and also to control the volume of the sound produced by the instrument.

It is a further object of my invention to provide a monophonic electronic musical instrument having volume control apparatus which is simple to operate and inexpensive to produce and maintain.

Further objects and advantages of my invention will become apparent as the following description proceeds. The features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In carrying out the objects of my invention, in a first form thereof, I provide volume control apparatus for a monophonic electronic musical instrument including a mouthpiece comprising a body having a main axial air flow passageway therethrough. A secondary air flow passageway through the body of the mouthpiece into the main passageway forms an aspirator, air being drawn through the secondary passageway into the main passageway in proportion to air flow through the passageway. A fuse wire forming a branch of a bridge circuit in the input of a DC. amplifier is located in the opening, the wire being cooled by the air drawn through the opening. As the flow rate of the air blown through the main passageway is varied, the temperature, and hence the resistance, of the fuse wire is modulated accordingly. The changes in resistance of the fuse wire unbalances the bridge circuit, causing, in turn, a modulated output from the DC. amplifier. The output load for the DC. amplifier is a lamp whose varying radiation of light energy is sensed by a photoelectric cell comprising part of the volume control circuit of an AF amplifier and speaker arrangement. Thus, the player, by modulating the flow rate of the air blown through the main passageway in the mouthpiece can control the volume of the instrument.

In another form of the invention, the mouthpiece comprises a body having a passageway in which a cylindrical chamber is located. A spring-biased, electrically conductive piston is moved axially against the bias of the spring in proportion to the flow rate of the air in the passageway. A conductive strip and a resistive strip are axially disposed in the walls of the chamber, being electrically connected by the piston. The series-connected resistive strip, piston, and conductive strip form a branch of a bridge circuit in the input of a DC amplifier, thus serving the same function as the fuse wire and aspirator in the embodiment described above. As the flow rate of the air blown through the passageway is varied, the piston is axially displaced in proportion to the variations thereof. Thus, the length, and hence the resistance, of the resistive strip in the branch of the bridge circuit is modulated in accordance with the variations in the flow rate of the air in the passageway. The remainder of the system is as described above with respect to the first embodiment.

For a better understanding of my invention, reference may be made to the accompanying drawings in which:

FIGURE 1 is a schematic view of the electronic musical instrument.

FIGURE 2 is a partial schematic view of the volume control apparatus for the instrument, with the mouthpiece for the instrument being shown in section.

FIGURE 3 is a section view of a modified form of the mouthpiece for the pitch selector.

FIGURE 4 is a section view taken on lines 44 in FIGURE 3.

Referring to the drawings, FIGURE 1 schematically illustrates the entire monophonic electronic musical instrument of which my invention forms a part. A pitch selector is shown at 6 in the form of a clarinet. The pitch selector comprises a plurality of keys 8 which the player operates to select the desired pitch to be played by the instrument. Whereas a clarinet has been illustrated, it is evident that the pitch selector 6 might be in the form of a saxophone or any of a variety of other instruments, or

even a totally new pitch selector designed specifically for use with my instrument.

Each of the keys 8 is electrically connected by leads 9 to a tone generator and control, shown in FIGURE 1 in black box form at 10. The tone generator and control may be of the formant type, or another of the suitable types of commercially available electronic systems designed for such a purpose. Because this aspect of the electronic instrument forms no part of this invention, it will not be described herein.

This invention is concerned with the apparatus for controlling the volume of the output of the instrument. This apparatus is shown in FIGURES 1 and 2 as comprising a mouthpiece 12 electrically connected by leads 13 to a volume control means, shown in black box form in FIG- URES l and 2 at 14. Completing the schematic in FIG- URE 1, the output of the volume control means 14 is fed to a conventional audio frequency (AF) amplifier and speaker 16.

This invention accomplishes the control of the volume of the instrument output solely by means of the breath of the player. A first form of the invention, shown in FIGURE 2, comprises a mouthpiece 12 for the pitch selector 6 having a body 18 in which an axial main air flow passageway 20 is formed. The rate of air flow through the main passageway 20 will increase or decrease in accordance with the changes in volume desired by the player. A secondary air flow passageway 22 formed in the body 18 of the mouthpiece 12 enters the main passageway 20 at right angles thereto, forming an aspirator having the effect of causing air to be drawn through the secondary passageway 22 into the main passageway 20 in proportion to the variations in the air flow rate in the main passageway 20.

A fuse wire 24 disposed in the secondary passageway 22 is energized through leads 25 from a DC. amplifier 26 forming part of the volume control means 14. From well known principles the resistance of the fuse wire 24 increases directly with its temperature. Thus, the air passing through the secondary passageway 22 at a rate proportional to the flow rate of air through the main passageway 20 will cool the fuse wire 24 proportionally, causing its resistance to be modulated in accordance with the variations in the flow rate of air through the main passageway 20.

The fuse wire 24 constitutes one branch of a conventional bridge circuit (not shown) in the input of the DC. amplifier. As the change in resistance of the fuse wire 24 unbalances the bridge circuit, the DO. amplifier 26 will, as is well known, receive a modulated input signal from the unbalanced bridge.

The output load of the DC. amplifier 26 is an incandescent lamp, shown schematically in FIGURE 2 at 28. It is evident that the light energy radiated from the lamp 28 will be modulated in accordance with the input to the DC. amplifier from the unbalanced bridge circuit.

A photosensitive cell 30 is positioned to sense the light energy being radiated from the lamp 28. The cell 30 is included as a resistive element in the volume control circuit of the AF amplifier. The resistance of the cell 30, varying in accordance with the modulated level of light energy impinging upon the cell 30, will cause the output of the AF amplifier to vary accordingly. Thus, the output volume of the AF amplifier (and speaker) Will be modulated proportionally to the flow rate of air through the main passageway 20, as sensed by the fuse wire and aspirator arrangement in the mouthpiece 12.

In a second embodiment of my invention (see FIGURE 3), another means for sensing the varying flow rate of air through a passageway through the mouthpiece is illustrated. In this embodiment a modified mouthpiece 32 comprises a body 34, an axial air flow passageway 36, and a piston 38 disposed in a cylindrical chamber 40 at the rear portion of the passageway 36. The piston 38 is 4 spring-biased by a spring 42 atfixed to a post 44 at the rear of the chamber 40. Referring to FIGURE 4, the piston 38 will be seen to have an aperture 46 formed therein which allows air to escape beyond the piston 38 and out through the rear of the mouthpiece 32.

An electrically conductive strip 48 and an electricallly resistive strip 50 are axially dispensed in diametrically opposed sides of the cylindrical chamber 40. The serially joined resistive strip 50, piston 38, and conductive strip 48 are connected by means of leads 52 in a bridge circuit in the input of a DC. amplifier, functioning as did the fuse wire 24 in the above-described embodiment.

In operation, as the player blows into the passageway 36 with varying force, the piston 38 is displaced axially against the bias of spring 42 by an amount, at any instant, proportional to the flow rate of air in the passageway 36. Thus, the piston 38, moving back and forth along the resistive strip 50, will act as a potentiometer, regulating the amount of resistance in the branch of the bridge circuit at the input to the DC. amplifier 26. As in the abovedescribed first embodiment, the DC amplifier will receive an input signal modulated in proportion to the varying flow rate of air in the passageway 36. The operation of the volume control means to amplify and integrate the input signal from the bridge circuit is the same as described above with respect to the first embodiment.

Thus I have provided volume control apparatus for a monophonic electronic musical instrument with which the volume output of the instrument can be controlled solely by the breath of the player.

My invention is not limited to the particular details of the construction of the embodiment illustrated and I contemplate that various and other modifications and applications will occur to those skilled in the art. It is therefore my intention that the appended claims shall cover such modifications and applications as do not depart from the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Volume control apparatus for a monophonic electronic musical instrument including an AP amplifier comprising:

(a) a mouthpiece comprising:

(1) a body,

(2) a main air flow passageway through said body,

(3) a secondary passageway in said body communicating with said main passageway, and

(b) volume control means responsive to variations in the flow rate of air through said main passageway, said means including a sensor in said secondary passageway, said means having an electrical output to the amplifier controlling the volume of the amplifier output in proportion to the variations in the flow rate of air blown through said air flow passageway.

2. The device defined in claim 1 wherein said main and secondary passageway form an aspirator, air being drawn into said main passageway through said secondary passageway by the flow of air through said main passageway.

3. Volume control apparatus for a monophonic electronic musical instrument including an AF amplifier comprising:

(a) a mouthpiece comprising:

(1) a body, and (2) an air flow passageway through said body,

(b) volume control means comprising:

(1) sensing means responsive to variations in the flow rate of air through said passageway,

(2) a DC. amplifier receiving an input from said sensing means,

(3) am incandescent lamp forming the output load of said D.C. amplifier, the light energy radiated from said lamp being modulated in accordance with the variations in the flow rate of air in said passageway,

(4) a photosensitive cell constituting a resistance in the volume control circuit of said AF amplifier, said cell being positioned to receive light energy from said lamp, whereby the volume of the AF amplifier output is proportional to the resistance of said cell, and hence to the modusageways forming an aspirator causing air to be drawn into said main passageway through said secondary passageway in proportion to the air flow through said main passageway, and

(b) volume control means comprising:

(1) sensing means responsive to variations in the flow rate of air through said passageway, said sensing means comprising a fuse wire in said secondary passageway, the resistance of said fuse wirevarying in proportion to the flow rate of arr 1n said secondary passageway, said fuse w1re constituting a branch of a bridge circuit,

(2? a D.C. amplifier, said D.C. amplifier receivmg an input from said bridge circuit which is proportional to the variations in the flow rate of air in said passageway,

(3) an incandescent lamp forming the output load of said D.C. amplifier, the light energy radiated from said lamp being modulated in accordance with the variations in the flow rate of air in said passageway, and

(4 a photosensitive cell constituting a resistance In the volume control circuit of said AF amplifier, said cell receiving light energy from said lamp, whereby the volume of the AF amplifier output is proportional to the resistance of said lated radiation from said lamp and the flow rate of air through said passageway. 4. The device defined in claim 3 wherein said sensing means comprises a pneumatic piston regulating a variable resistance in a branch of a bridge circuit in the input to said D.C. amplifier, whereby the varying resistance in said branch causes said bridge circuit to be unbalanced and said D.C. amplifier to receive an input modulated in accordance with the flow rate in said passageway.

5. The device defined in claim 3 wherein said sensing means comprises:

(a) a spring-biased, electrically conductive pneumatic piston in said passageway, (b) an electrically conductive strip oriented along the axis of said mouthpiece in sliding engagement with said piston, and v (c) an electrically resistive strip insulated from said conductive strip and oriented along the axis of said mouthpiece in sliding engagement with said piston, said conductive strip, said piston, and said resistive strip being serially arranged in a branch of a bridge circuit in the input to said D.C. amplifier, whereby cell, and hence to the modulated radiation from said lamp and the flow rate of air through said mam passageway.

References Cited said piston is displaced along said strips in accordance with variations in the flow rate of air in said passageway, the varying resistance in said branch being UNITED STATES PATENTS thus generated causing said bridge circuit to be un- 780862 1/1905 Cameronbalanced and said D.C. amplifier to receive an input 2,301,184 11/1942 Arnoldmodulated in accordance with said flow rate in said 2i455:032 1'1/1943 Williamspassageway. 5 ,490 7/ 1950 Hanert. 6. Volume control apparatus for a monophonic elec- 2,776,591 1/1957 McBride. tronic musical instrument including an AF amplifier com- 29,020 1/ 1966 Jenny 34 1 2 X prising: 10 4 5/1966 Jenny 84 1 27 X (a) a mounthpiece comprising:

1) a b d ARTHUR GAUSS, Primary Examiner. g a yf alr fl passageway through 881d D. D. FORRER, AssistantExaminer. (3) a secondary passageway in said body coms CL XR' municating with said main passageway, said pas- 84 ,1 ()9 1 1 1 13 

